Ingredients:

  • 3 large yellow onions, thinly sliced (about 900g / 2 lbs)
  • 4 tablespoons unsalted butter (56g / 2 oz)
  • 1 tablespoon olive oil (15 ml)
  • 1 teaspoon granulated sugar (4g)
  • ½ teaspoon kosher salt (3g)
  • ¼ teaspoon black pepper (1g)
  • 2 tablespoons dry sherry (30 ml)
  • 1 cup beef broth (240ml / 8 fl oz)
  • 1 pound elbow macaroni (450g)
  • 6 tablespoons unsalted butter (85g / 3 oz)
  • 6 tablespoons all-purpose flour (48g)
  • 3 cups whole milk (720ml / 24 fl oz)
  • 1/2 teaspoon nutmeg, freshly grated (1g)
  • 1/2 teaspoon salt (3g)
  • 1/4 teaspoon black pepper (1g)
  • 8 ounces Gruyere cheese, shredded (225g)
  • 4 ounces sharp cheddar cheese, shredded (110g)
  • 2 ounces parmesan cheese, grated (55g)
  • 1/2 cup Panko breadcrumbs (25g)
  • 2 tablespoons melted butter (30ml)
  • Fresh thyme sprigs, for garnish

Instructions:

  1. Melt butter and olive oil in a large pot over medium heat. Add onions, sugar, salt, and pepper. Cook, stirring occasionally, until onions are deeply golden brown and caramelized (about 30-40 minutes). Deglaze the pan with sherry (if using) and scrape up any browned bits. Stir in beef broth and simmer for 5 minutes. Remove from heat and set aside.
  2. Cook macaroni according to package directions until al dente. Drain well.
  3. Melt butter in the saucepan over medium heat. Whisk in flour and cook for 1-2 minutes to make a roux. Gradually whisk in milk until smooth. Bring to a simmer, stirring constantly. Reduce heat to low and simmer for 5 minutes, stirring occasionally, until slightly thickened. Stir in nutmeg, salt, and pepper. Remove from heat.
  4. Add Gruyere, cheddar, and Parmesan cheese to the sauce, stirring until melted and smooth.
  5. Stir the cooked macaroni and caramelized onions into the cheese sauce. Pour the mixture into a prepared baking dish. If using topping, combine panko breadcrumbs and melted butter, then sprinkle evenly over the mac and cheese. Bake in a preheated oven at 350°F (175°C) for 20-25 minutes, or until bubbly and golden brown.
  6. Let cool slightly before serving. Garnish with fresh thyme sprigs. Enjoy your french onion soup mac and cheese!